Im debating on a 6.8 upper for another ar build. Seeing if yall got any experience with it. Is it worth having one in your collection. Appreciate any input

Yes.

X3

Lots and lots of info on the 6.8 here in this section of the forum. Even those that use to argue tooth and nail that the heavier grain 5.56 have no jumped ship.

I like mine.

6.8 or 300BO? i have been thinking about bulding too but cant decide.

I'm one of the biggest 270 fans there is. But comparing the 6.8 to the 300 black out, the blackout has a lot more going for it. 300 ammo is much cheaper, and you get a better bullet selection and heavier bullet options than the 6.8. Plus 6.8 ammo is very hard to find these days. If you reload, the 300 can do most anything like, plus run the subsonic ammo. I'd vote 300. And some guys would be shocked, because I am a tried and true 270 fan.

And with the 300 all you got to do is have a complete upper with bcg and you can use the same mags as the 5.56? is that true?

Well when you come right down to it you really dont even need a complete upper with the 300. Just a simple barrel and muzzle device swap would be all thats needed.

I still think the 6.8 is a better hunting round though.

Yes. If you have a complete AR-15 in 223 already, you could just install a new barrel. Or, just buy a fully built upper and use your existing lower. This way you can put on a dedicated scope for each caliber without having to re-sight in.

And yes, they run out of your standard 223 magazines.

as long as you put it back on the same spot as before on your upper rail it should hold zero right?

I'm drinking the 300BO koolaid right now and just finished my second complete carbine.
Thankfully, the next batch of barrels have started flowing again as I received another CMMG yesterday and the other one I have ordered shipped yesterday also!

Back to subject at hand....
I've looked at the 6.8 and liked what I saw and was ready to pull the trigger when the 300BO came around and fit my needs well.
I reload and like to experiment methodically so ammo WAS NOT that much of a concern but the wide range of .308 bullets is appealing.
I'll build a 6.8 someday to play with.

Time to build. other than $ why not build a few

204 Ruger
5.56
6.5 Grendel
6.8 SPC
300 blackout
30 AR Remington
458 Socom
450 Bushmaster
50 Beowolf

oh forgot the WSSMs also

Theortically, yes. But by the time you switch just the barrel, and remount the scope, you normally get a shift in POI from different bullets and calibers. I want a different scope anyway from my 223 and 300 black out, so I need seperate uppers with each having their own scope.

Before going the route of the 6.8 I would look at the 6.5 grendel. The patent was released in February by Alexander Arms. I am in the process of getting my grendel and can't wait.

Working on my new 6.8 SBR build now... Should have everything in next few days... Can't wait!!!

what kind of groups are you getting with the cmmg barrels at 100 yards?

which one of these are more affordable to shoot if you dont have the means to reload? besides 5.56

300 blackout probably

300 blackout has some factory 65 cent/round ammo. The bolt and the magazines are the same as the 5.56NATO.

The 6.8 spc does have better ballistics though. It probably is a little better hunting round, but 300 blackout has some good sub-sonic rounds, and very good performance through a SBR (two areas where .223 kind of falls flat).

There is a LOT of money and advertising behind the 300 blackout right now.

Unless you do a lot of hunting, the cost of ammo isn't going to be that big of a factor, and you can use .223 in Texas anyways.

I was part of that Spikes lower buy recently and this will be my first build from the ground up.
I am torn but I think I'm leaning towards the 6.5 Grendel.
The 6.8 and 300 just aren't doing it for me right now.

Sub MOA with the 300BO.
First three shots out of new barrel shot 1.1 MOA and got better as I cleaned and broke it in.
I finished the second CMMG barrelled 300BO yesterday but the weather was too crappy to do any shooting.
I have an E R Shaw 16" 300BO barrel that should be here Monday.
After I finish building and breaking them in, I will report on differences, if any...

Overall, I am extremely happy with the CMMG barrels so far...